Prince George Is Turning 1! Inside Life Today with the Little Heir

He's walking, babbling – and still waking up much, much earlier than his parents would like.

As Prince George approaches his first birthday on Tuesday, the future heir to the British throne is growing into a spirited toddler whose every milestone is met with pride by his mom and dad, Princess Kate and Prince William.

"As for any new parent, it's exciting and a joy to be a part of," a palace source tells PEOPLE in this week's cover story. "It's a wonderful thing going through your baby's first year."

For the heir to the British throne (behind his dad and grandfather, Prince Charles), it has been a year filled with adventure (the royal tour Down Under), sweet moments (singing "Row, Row, Row Your Boat" with Mom) and sleepless nights (for which William recently shared his coping strategy).

And like many parents of a nearly 1-year-old, William and Kate, both 32, have begun planning for baby no. 2.

Although the palace won't comment on the ever-present pregnancy rumors, a source close to the couple confirms they plan to give George a sibling not too long from now, but "they don't say when."

Still, the pieces are in place: William is preparing to start a long-term job with an air ambulance service, a job close to the couple's country home, Anmer Hall.